See exactly how your money grows.

No black boxes, no sales pitch. Free financial calculators built to show their work. Every formula is visible, every assumption is stated, and every number is tested before it's published.

Get new calculators and guides in your inbox

Occasional, useful, no spam. Double opt-in, unsubscribe anytime.

All calculators

100 calculators and counting.

Retirement Calculator Enter your age, savings, and monthly contribution to see what your retirement balance could become, shown both in future dollars and in today’s purchasing power. IRA Growth Calculator See how regular IRA contributions can grow over time with monthly compounding. Mega Backdoor Roth Calculator Calculate the extra after-tax 401(k) contributions you can make and convert to Roth, on top of your normal deferral and employer match. Coast FIRE Calculator Coast FIRE is the amount invested today that grows into your full retirement target on its own, letting you stop adding new money. FIRE Number Calculator Your FIRE number is the portfolio that can cover your annual expenses at a safe withdrawal rate, which is 25 times expenses at the classic 4% rate. Retirement Drawdown Calculator See how long your retirement savings last under a yearly withdrawal that rises with inflation, at your expected return.
Compound Interest Calculator See how a starting balance plus regular contributions grows with compound interest over time. Investment Growth Calculator Project how an investment portfolio grows when you invest a fixed amount each month. Inflation Calculator See what a future amount of money is worth in today’s purchasing power after inflation. Rule of 72 Calculator The Rule of 72 estimates how many years it takes your money to double at a given annual return. Savings Goal Calculator Find the monthly amount you need to save to reach a target by a chosen date. Time to Reach a Savings Goal Find how long it takes to reach a target, like your first $1 million, at your current savings rate.
Mortgage Calculator Calculate your true monthly payment with principal, interest, tax, insurance, PMI, and HOA, and see when PMI drops off. Mortgage Payoff Calculator See how much time and interest you save by adding extra principal to your mortgage payment each month. Rent vs Buy Calculator Compare renting and buying by ending net worth, counting the return you could earn by investing the down payment and monthly savings instead. Home Affordability Calculator Find the home price your income supports, using the front-end and back-end debt-to-income limits that lenders apply. Refinance Calculator See how much refinancing saves each month, how long it takes to earn back the closing costs, and the effect over the life of the loan. Biweekly Mortgage Calculator See how paying half your mortgage every two weeks pays it off years early, saves interest, and removes PMI sooner by reaching 20 percent equity faster.
Federal Income Tax Calculator (2026) Calculate your federal income tax on a given taxable income, with a clear bracket-by-bracket breakdown. Effective vs Marginal Tax Rate Calculator (2026) Compare your marginal tax bracket with your true effective rate, the two numbers most people mix up. Tax Bracket Calculator (2026) Find out which federal tax bracket your income falls into for 2026. Bonus Tax Calculator Your bonus is withheld at a flat 22%, but your real tax on it depends on your bracket. This shows the gap. Roth Conversion Calculator See the federal tax cost of a Roth conversion and the bracket it pushes you into this year. Self-Employment Tax Calculator (2026) Work out your self-employment tax for 2026, the 15.3 percent that covers Social Security and Medicare when you work for yourself.
RSU Calculator Your vesting RSUs are withheld at a flat 22%, but your real tax depends on your bracket. This shows the shortfall you may owe at filing. ESPP Calculator An ESPP lets you buy company stock at a discount. With a lookback, your effective discount and return can be much larger than the stated rate. Salary to Hourly Calculator Turn a yearly salary into an hourly rate, and see the weekly, biweekly, and monthly pay it works out to. Raise Calculator See what a raise is really worth once inflation is removed, in both a real percentage and today buying power. Freelance Rate Calculator Find the hourly rate a contractor needs to match a salary, once payroll tax, benefits, and unbillable time are covered. ISO AMT Calculator (2026) See the alternative minimum tax that exercising incentive stock options can trigger, from the bargain element you never received in cash.
529 College Savings Calculator Project how a 529 plan grows with regular contributions before college starts. Student Loan Payoff Calculator See how paying extra each month gets you out of student debt faster and cuts total interest. Credit Card Payoff Calculator See how long a credit card takes to pay off and how much extra payments accelerate it. Debt Snowball vs Avalanche Calculator Enter your debts and a monthly budget to see the snowball and avalanche side by side, with the months and interest each one costs. Life Insurance Calculator Estimate how much life insurance you need with the DIME method, adding debt, income, mortgage, and education, then subtracting what you have. Personal Loan Calculator See the monthly payment, total interest, and payoff time on a personal loan, and how much extra payments save.

Shows its work

Every calculator lists its formula, a worked example, and the exact assumptions behind the result.

Tested before it ships

Each result is checked against known-correct values, so the numbers you see are numbers you can trust.

Runs your numbers

Change an input and the result updates instantly, right in your browser. Nothing you type is sent to us.

Resources

Guides that explain the concept behind a calculator, and visual resources that make one idea click. Every number is drawn from the same tested engine the calculators use.

Browse resources